⚠️ Drop DiscoveryRESTMapper

The discovery restmapper was unused except for two places that we missed
(when creating a cache directly as opposed through the manager and in a
test). The discovery restmapper only ever loads mappings once during
startup and is unable to reload them if they change. It also isn't lazy
and we don't want anyone using it.

pkg/cache/cache.go

@@ -412,7 +412,7 @@ func defaultOpts(config *rest.Config, opts Options) (Options, error) {
 	// Construct a new Mapper if unset
 	if opts.Mapper == nil {
 		var err error
-		opts.Mapper, err = apiutil.NewDiscoveryRESTMapper(config, opts.HTTPClient)
+		opts.Mapper, err = apiutil.NewDynamicRESTMapper(config, opts.HTTPClient)
 		if err != nil {
 			return Options{}, fmt.Errorf("could not create RESTMapper from config: %w", err)
 		}

pkg/client/apiutil/apimachinery.go

@@ -31,11 +31,9 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/runtime/serializer"
-	"k8s.io/client-go/discovery"
 	"k8s.io/client-go/dynamic"
 	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
 	"k8s.io/client-go/rest"
-	"k8s.io/client-go/restmapper"
 )
 
 var (
@@ -60,25 +58,6 @@ func AddToProtobufScheme(addToScheme func(*runtime.Scheme) error) error {
 	return addToScheme(protobufScheme)
 }
 
-// NewDiscoveryRESTMapper constructs a new RESTMapper based on discovery
-// information fetched by a new client with the given config.
-func NewDiscoveryRESTMapper(c *rest.Config, httpClient *http.Client) (meta.RESTMapper, error) {
-	if httpClient == nil {
-		return nil, fmt.Errorf("httpClient must not be nil, consider using rest.HTTPClientFor(c) to create a client")
-	}
-
-	// Get a mapper
-	dc, err := discovery.NewDiscoveryClientForConfigAndClient(c, httpClient)
-	if err != nil {
-		return nil, err
-	}
-	gr, err := restmapper.GetAPIGroupResources(dc)
-	if err != nil {
-		return nil, err
-	}
-	return restmapper.NewDiscoveryRESTMapper(gr), nil
-}
-
 // IsObjectNamespaced returns true if the object is namespace scoped.
 // For unstructured objects the gvk is found from the object itself.
 func IsObjectNamespaced(obj runtime.Object, scheme *runtime.Scheme, restmapper meta.RESTMapper) (bool, error) {

pkg/handler/eventhandler_test.go

@@ -54,7 +54,7 @@ var _ = Describe("Eventhandler", func() {
 
 		httpClient, err := rest.HTTPClientFor(cfg)
 		Expect(err).ShouldNot(HaveOccurred())
-		mapper, err = apiutil.NewDiscoveryRESTMapper(cfg, httpClient)
+		mapper, err = apiutil.NewDynamicRESTMapper(cfg, httpClient)
 		Expect(err).ShouldNot(HaveOccurred())
 	})